A diesel particulate filter is a device that removes diesel particulate matter or soot from the exhaust of a diesel engine. Segmented diesel particulate filters are assembled by joining an array of individual segments with an adhesive cement. In an assembly process, the cement is applied to a side surface of a segment, and another segment is pressed into the cement. This is repeated to build up arrays of segments.
When joining the segments, it is desirable to use excess cement to ensure the cement seams are fully filled without air voids. When the segments are joined, the excess cement overflows from the seam as the segments are pressed together. This excess cement must be removed so the cement in each seam is substantially flush to the adjoining segments.
It is known for an operator to use a standard drywall knife or similar conventional scraper to remove excess cement overflows. However, using a standard drywall knife can easily catch a corner of a segment, especially when the faces of the segments are not all aligned in exactly the same plane. If an operator uses a standard drywall knife to scrape the surface, when pressure is applied to the knife, its sharp edge may forcefully contact the brittle corners of segments that are not perfectly aligned with the adjoining segments, causing the corners of the segments to chip and break away. As these corners are fragile, an operator performing the scraping must use caution to adjust the angle of approach and pressure applied to the scraper blade to prevent damage to the segments. It is desirable to implement an automated scraping process; however, since so much care is required to scrape the excess cement, and an operator must visually assess the surface he or she is scraping, it has previously been difficult to automate this scraping process.
Thus, what is needed is a method of scraping excess pasty material, such as cement, from a seam joining two substrates without causing damage to the surfaces of the substrates, particularly to the edges, and also a method of scraping that allows for the scraping process to be automated if desired.